The present invention relates to a flat panel display device having electron beam guides and particularly to such a display device in which the beam guides include means for achieving precision injection of the electrons into the guides.
U.S. Pat. No. 4,031,427 to T. O. Stanley, issued June 21, 1977, entitled "Flat Cathode Ray Tube" describes a flat, cathodoluminescent display device which includes in an evacuated envelope beam guides extending along the back wall of the envelope from a gun structure which generates electrons and directs the electrons as beams in the beam guides. The beam guides confine the electrons in the beams as the beams travel along paths parallel to the front wall of the envelope and selectively deflect the beams toward a phosphor screen on the front wall at selected points along the paths of the beams.
Copending application for U.S. Patent, Serial No. 671,358 of W. W. Siekanowicz et al, filed March 29, 1976, now U.S. Pat. No. 4,088,920, issued May 9, 1978, entitled "Flat Display Device with Beam Guide" describes a beam guide for use in the display device of the type described in U.S. Pat. No. 4,031,427. The beam guide includes a pair of spaced, parallel plates extending along and spaced from the back wall of the envelope. The plates have a plurality of aligned openings therethrough with the openings being arranged in rows extending longitudinally along the paths of the beams. Each longitudinal row of the openings constitutes a separate beam guide.
Copending application for U.S. Pat., Ser. No. 784,365 of R. A. Gange, filed Apr. 4, 1977, entitled "Cathode Structure and Method of Operating the Same" discloses a gun structure for use in the display device of the type described in U.S. Pat. No. 4,031,427. The gun structure includes a line cathode having modulation or control electrodes spaced along the line cathode. Potentials applied to the modulation of control electrodes cause the electrons generated by the cathode to be emitted therefrom in the form of beams. The gun structure may include isolation electrodes between the modulation electrodes to assist in confining the electrons in the beams emitted from the gun structure and guiding the beams into the guide structure.
In the use of the gun structure of the Gange application Ser. No. 784,365 and the beam guide of the Siekanowicz et al application Ser. No. 671,358, now U.S. Pat. No. 4,088,920, issued May 9, 1978, in the display device described in U.S. Pat. No. 4,031,427, a problem has arisen with regard to achieving accurate injection of the electron beams from the gun structure into the beam guides along the longitudinal rows of openings in the guide plates. To achieve accurate injection of the electron beams it is not only necessary to provide high precision of the sizes and relative positions of the modulation and isolation electrodes of the gun structure, but also high precision of the position of the gun structure electrodes with respect to the plate openings of the beam guides. Such need for high precision complicates the making and assemblying of the parts of the display device. Therefore, it would be desirable to have a simpler construction of the gun structure and/or the beam guides which would achieve the accurate injection of the electron beams into the beam guides.